Sens. John McCain, Bob Corker, and Richard Burr all made separate statements on Tuesday about Trump's unexpected decision.

"While the President has the legal authority to remove the Director of the FBI, I am disappointed in the President's decision to remove James Comey from office," McCain, an Arizona senator, said in a statement. "James Comey is a man of honor and integrity, and he has led the FBI well in extraordinary circumstances."

"I have long called for a special congressional committee to investigate Russia's interference in the 2016 election," the statement continued. "The president's decision to remove the FBI Director only confirms the need and the urgency of such a committee."

Corker expressed similar skepticism of Trump's decision.

"While the case for removal of Federal Bureau of Investigation Director James Comey laid out by Deputy Attorney General Rod J. Rosenstein was thorough, his removal at this particular time will raise questions," Corker, of Tennessee, said in a statement. "It is essential that ongoing investigations are fulsome and free of political interference until their completion, and it is imperative that President Trump nominate a well-respected and qualified individual to lead the bureau at this critical time."

Burr, the chairman of the Senate Intelligence Committee, said he was "troubled" by "the timing and reasoning" of Comey's firing.

"I have found Director Comey to be a public servant of the highest order, and his dismissal further confuses an already difficult investigation by the Committee. In my interactions with the Director and with the Bureau under his leadership, he and the FBI have always been straightforward with our Committee. Director Comey has been more forthcoming with information than any FBI Director I can recall in my tenure on the congressional intelligence committees. His dismissal, I believe, is a loss for the Bureau and the nation," Burr said.

Deputy Attorney General Rod Rosenstein, in a letter to Attorney General Jeff Sessions, pointed to Comey's July 2016 public announcement of his recommendation regarding the investigation into then-presumptive Democratic presidential nominee Hillary Clinton's use of a private email server while she served as secretary of state.

The deputy attorney general said Comey was "wrong to usurp the attorney general's authority" by going public with the FBI's recommendation to not bring charges forth against Clinton for her use of the server.

The White House said Trump was acting on Rosenstein's and Sessions' recommendation to fire Comey.